How is the effect called where the product of density, area and velocity of a streamline duct are constant?
If a system is in a condition of steady flow, it is possible to write what is known as a continuity equation. This is a relatively simple concept if the flow is steady, then the flow rate at every point through the system must be the same. If it wasn't, there would not be steady flow.
Imagine air flowing through a narrowing duct. To get the same mass flow rate through the thinner section of the duct, the velocity must have increased. The mass flow depends on the velocity of the air (V), the density of the air (ρ) and the cross-sectional area of the tube (A). Thus:
- A V ρ = Mass Flow = A constant value
In airflows of up to about 300 kt, there is only a small change in air density. So, we can reasonably assume that our simple narrowing duct example holds true up to this speed. Beyond this speed, compressibility effects start come into play.
Your Notes (not visible to others)
This question has appeared on the real examination, you can find the related countries below.
Use Keyboard Shortcuts
